Re: [U-Boot] FAT filesystem support on SPI flash

2014-02-25 Thread Vasili Galka
Dear Jagan,

I'm not sure I fully understand your question.
SPI flash is just a medium that has sectors/pages/blocks (call it
however you want). You are free to store data with any structure you
like on it. So if you like - you can store FAT file-system on it.
That's true that maybe storing a FAT file-system that has frequent
write operations on SPI flash is not a good idea, both because of
speed and because of flash wear. But that is an entirely different
question. There are still many cases when the data does not change
frequently and FAT on SPI flash can be useful.

Best,
Vasili

On Sun, Feb 23, 2014 at 7:49 PM, Jagan Teki jagannadh.t...@gmail.com wrote:
 On Sun, Feb 23, 2014 at 7:07 PM, Vasili Galka vas...@visionmap.com wrote:
 Hi,

 On our system, we are interested in keeping all files, including the OS 
 image and U-Boot second stage on FAT filesystem residing on a SPI flash.

 I'm not a file-system expert, but I've a basic question like how
 does/well a SPI flash(mtd) device have
 FAT support on it. Generally flash file-systems were categories to do
 the job right?


 I have not found existing U-Boot support for such functionality. Have I 
 missed it?

 In any case, I'm willing to implement this, do you see it reasonable 
 incorporating such code into U-Boot? (if it passes review of course)

 I note about design: As our chip (TI's AM335x) does not support direct boot 
 from FAT stored on SPI, I plan reserving section at the beginning of SPI 
 flash for the first stage boot loader and having the filesystem after it.

 thanks!
 --
 Jagan.
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Re: [U-Boot] FAT filesystem support on SPI flash

2014-02-25 Thread Vasili Galka
Dear Wolfgang,

1. So, my understanding is that fatload/fatls/etc have only MMC/SATA
support now? No support for MTD?

2. Where can I find the description of device driver model you
mention? When is it planned to be adopted?

Best,
Vasili

On Sun, Feb 23, 2014 at 7:23 PM, Wolfgang Denk w...@denx.de wrote:
 Dear Vasili,

 In message d69e639dbb744e9ca4c7742f42c82...@ex13.visionmap.co.il you wrote:

 On our system, we are interested in keeping all files, including the OS 
 image and U-Boot second stage on FAT filesystem residing on a SPI flash.

 I have not found existing U-Boot support for such functionality. Have I 
 missed it?

 We do not have FAT suppot on flash devices yet.

 In any case, I'm willing to implement this, do you see it reasonable 
 incorporating such code into U-Boot? (if it passes review of course)

 I think the best way to implement this would require a two staged
 approach: in the first stage, U-Boot should adapte the device driver
 model we've been waiting for so long; in the second stage, the file
 system support would more or less fall into place on to of the then
 existing storage device drivers.

 Best regards,

 Wolfgang Denk

 --
 DENX Software Engineering GmbH, MD: Wolfgang Denk  Detlev Zundel
 HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
 Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
 When some people discover the truth, they just can't  understand  why
 everybody isn't eager to hear it.
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Re: [U-Boot] FAT filesystem support on SPI flash

2014-02-25 Thread Tom Rini
On Sun, Feb 23, 2014 at 01:37:53PM +, Vasili Galka wrote:
 Hi,
   
 On our system, we are interested in keeping all files, including the
 OS image and U-Boot second stage on FAT filesystem residing on a SPI
 flash.
 
 I have not found existing U-Boot support for such functionality. Have
 I missed it?
 
 In any case, I'm willing to implement this, do you see it reasonable
 incorporating such code into U-Boot? (if it passes review of course)
 
 I note about design: As our chip (TI's AM335x) does not support direct
 boot from FAT stored on SPI, I plan reserving section at the beginning
 of SPI flash for the first stage boot loader and having the filesystem
 after it.

The high level suggestion is to review your design decision as this
seems rather questionable.  Today our FAT code doesn't work directly on
flash, but I imagine a day or two of hacking might allow it to work.
But FAT isn't designed to be on flash directly and you really want a
good reason to not be using a flash filesystem on SPI.

-- 
Tom


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[U-Boot] FAT filesystem support on SPI flash

2014-02-23 Thread Vasili Galka
Hi,

On our system, we are interested in keeping all files, including the OS image 
and U-Boot second stage on FAT filesystem residing on a SPI flash.

I have not found existing U-Boot support for such functionality. Have I missed 
it?

In any case, I'm willing to implement this, do you see it reasonable 
incorporating such code into U-Boot? (if it passes review of course)

I note about design: As our chip (TI's AM335x) does not support direct boot 
from FAT stored on SPI, I plan reserving section at the beginning of SPI flash 
for the first stage boot loader and having the filesystem after it.

Best,
Vasili

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Re: [U-Boot] FAT filesystem support on SPI flash

2014-02-23 Thread Wolfgang Denk
Dear Vasili,

In message d69e639dbb744e9ca4c7742f42c82...@ex13.visionmap.co.il you wrote:
   
 On our system, we are interested in keeping all files, including the OS image 
 and U-Boot second stage on FAT filesystem residing on a SPI flash.
 
 I have not found existing U-Boot support for such functionality. Have I 
 missed it?

We do not have FAT suppot on flash devices yet.

 In any case, I'm willing to implement this, do you see it reasonable 
 incorporating such code into U-Boot? (if it passes review of course)

I think the best way to implement this would require a two staged
approach: in the first stage, U-Boot should adapte the device driver
model we've been waiting for so long; in the second stage, the file
system support would more or less fall into place on to of the then
existing storage device drivers.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH, MD: Wolfgang Denk  Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
When some people discover the truth, they just can't  understand  why
everybody isn't eager to hear it.
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Re: [U-Boot] FAT filesystem support on SPI flash

2014-02-23 Thread Jagan Teki
On Sun, Feb 23, 2014 at 7:07 PM, Vasili Galka vas...@visionmap.com wrote:
 Hi,

 On our system, we are interested in keeping all files, including the OS image 
 and U-Boot second stage on FAT filesystem residing on a SPI flash.

I'm not a file-system expert, but I've a basic question like how
does/well a SPI flash(mtd) device have
FAT support on it. Generally flash file-systems were categories to do
the job right?


 I have not found existing U-Boot support for such functionality. Have I 
 missed it?

 In any case, I'm willing to implement this, do you see it reasonable 
 incorporating such code into U-Boot? (if it passes review of course)

 I note about design: As our chip (TI's AM335x) does not support direct boot 
 from FAT stored on SPI, I plan reserving section at the beginning of SPI 
 flash for the first stage boot loader and having the filesystem after it.

thanks!
-- 
Jagan.
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